Use the closure tag for accumulators.

The first field of accumulators points out of the OCaml heap, so using
closures instead of tag-0 objects is better for the GC.

Accumulators are distinguished from closures because their code pointer
necessarily is the "accumulate" address, which points to an ACCUMULATE
instruction.

3 files changed, 10 insertions, 10 deletions

diff --git a/kernel/byterun/coq_interp.c b/kernel/byterun/coq_interp.c
index 40ddcbb213..1b6da7dd6f 100644
--- a/kernel/byterun/coq_interp.c
+++ b/kernel/byterun/coq_interp.c
@@ -193,6 +193,8 @@ if (sp - num_args < coq_stack_threshold) {                                     \
 #endif
 #endif
 
+#define Is_accu(v) (Is_block(v) && Tag_val(v) == Closure_tag && Code_val(v) == accumulate)
+
 #define CheckPrimArgs(cond, apply_lbl) do{         \
     if (cond) pc++;                                \
     else{                                          \
@@ -726,7 +728,7 @@ value coq_interprete
             accu = block;
             /* Construction of the accumulator */
             num_args = coq_extra_args - rec_pos;
-            Alloc_small(block, 3 + num_args, Accu_tag);
+            Alloc_small(block, 3 + num_args, Closure_tag);
             Code_val(block) = accumulate;
             Field(block, 1) = Val_int(2);
             Field(block, 2) = accu;
@@ -808,7 +810,7 @@ value coq_interprete
 
         /* Creation des blocks accumulate */
         for(i=0; i < nfunc; i++) {
-          Alloc_small(accu, 3, Accu_tag);
+          Alloc_small(accu, 3, Closure_tag);
           Code_val(accu) = accumulate;
           Field(accu, 1) = Val_int(2);
           Field(accu, 2) = Val_int(1);
@@ -957,6 +959,7 @@ value coq_interprete
         print_int(sizes & 0xFFFFFF);
         if (Is_block(accu)) {
           long index = Tag_val(accu);
+          if (index == Closure_tag) index = 0;
           print_instr("block");
           print_lint(index);
           pc += pc[(sizes & 0xFFFFFF) + index];
@@ -1062,7 +1065,7 @@ value coq_interprete
               Field(accu, 0) = Field(coq_global_data, *pc++);
               Field(accu, 1) = *sp++;
               /* Create accumulator */
-              Alloc_small(block, 3, Accu_tag);
+              Alloc_small(block, 3, Closure_tag);
               Code_val(block) = accumulate;
               Field(block, 1) = Val_int(2);
               Field(block, 2) = accu;
@@ -1126,7 +1129,7 @@ value coq_interprete
         mlsize_t i, size;
         print_instr("ACCUMULATE");
         size = Wosize_val(coq_env);
-        Alloc_small(accu, size + coq_extra_args + 1, Accu_tag);
+        Alloc_small(accu, size + coq_extra_args + 1, Closure_tag);
         for(i = 0; i < size; i++) Field(accu, i) = Field(coq_env, i);
         for(i = size; i <= coq_extra_args + size; i++)
           Field(accu, i) = *sp++;
@@ -1220,7 +1223,7 @@ value coq_interprete
             Field(block, 1) = accu;
             accu = block;
             /* We create the accumulator */
-            Alloc_small(block, 3, Accu_tag);
+            Alloc_small(block, 3, Closure_tag);
             Code_val(block) = accumulate;
             Field(block, 1) = Val_int(2);
             Field(block, 2) = accu;
@@ -1235,7 +1238,7 @@ value coq_interprete
       Instruct(MAKEACCU) {
         int i;
         print_instr("MAKEACCU");
-        Alloc_small(accu, coq_extra_args + 4, Accu_tag);
+        Alloc_small(accu, coq_extra_args + 4, Closure_tag);
         Code_val(accu) = accumulate;
         Field(accu, 1) = Val_int(2);
         Field(accu, 2) = Field(coq_atom_tbl, *pc);
diff --git a/kernel/byterun/coq_memory.c b/kernel/byterun/coq_memory.c
index 6233675c66..ae5251c252 100644
--- a/kernel/byterun/coq_memory.c
+++ b/kernel/byterun/coq_memory.c
@@ -108,7 +108,7 @@ value init_coq_vm(value unit) /* ML */
     init_coq_interpreter();
 
     /* Some predefined pointer code.
-     * It is typically contained in accumulator blocks whose tag is 0 and thus
+     * It is typically contained in accumulator blocks and thus might be
      * scanned by the GC, so make it look like an OCaml block. */
     value accu_block = (value) coq_stat_alloc(2 * sizeof(value));
     Hd_hp (accu_block) = Make_header (1, Abstract_tag, Caml_black);        \
diff --git a/kernel/byterun/coq_values.h b/kernel/byterun/coq_values.h
index bde6e14367..f07018711b 100644
--- a/kernel/byterun/coq_values.h
+++ b/kernel/byterun/coq_values.h
@@ -17,7 +17,6 @@
 #include <float.h>
 
 #define Default_tag 0
-#define Accu_tag 0
 
 #define ATOM_ID_TAG 0
 #define ATOM_INDUCTIVE_TAG 1
@@ -28,8 +27,6 @@
 #define ATOM_COFIX_TAG 6
 #define ATOM_COFIXEVALUATED_TAG 7
 
-/* Les blocs accumulate */
-#define Is_accu(v) (Is_block(v) && (Tag_val(v) == Accu_tag))
 #define Is_double(v) (Tag_val(v) == Double_tag)
 #define Is_tailrec_switch(v) (Field(v,1) == Val_true)